IDEXX Laboratories, Inc., located in Westbrook, Maine, provides veterinarians, researchers, and municipalities with analytical systems and diagnostic products and services. In 2008 the company introduced the Catalyst Dx Chemistry Analyzer, which performs 27 different tests of blood and urine for veterinary practices. This highly automated system features superior speed, throughput, and flexibility, freeing up staff while the system performs tests on multiple samples.
“The Catalyst Dx is the Cadillac of Instruments,” says Senior Mechanical Engineer Justin Griffin, “but we realized that we were missing an important segment of the market — smaller practices that want the capabilities of the Dx model but don’t need that level of throughput or automation. We set out to design a Catalyst model that would perform that same tests but was priced for that market.”
The goal for Griffin and the team developing the new Catalyst One was to cut manufacturing cost of the new system in half. That meant combining functions wherever possible. “The Dx model uses 14 separate motors for the processes it performs,” says Griffin. “The new model will be smaller and less automated and will forego features like an onboard touchscreen, but it will perform the same range of tests using just six motors. The heart of the new machine is a three-axis robot operated by four motors. That along with two additional motors and some very sophisticated engineering will allow the system to perform all the tasks needed to make the Catalyst One work. For example we are using a rack and pinion to convert the robot’s vertical actuation to horizontal motion.”
Development of the new system was a rigorous process that has taken about 30months. “We started out by conceptualizing the new design,” says Griffin. “We knew what the system had to do, but that those tasks had to be done differently. We also had to consider where to put the circuit boards within the smaller machine and where to park moving components when the machine wasn’t operating, to keep both the user and the robot safe when required cleaning was being done.
“We started by working out ideas on a whiteboard and paper and at the end of eight months had identified 17 top-level requirements, addressing issues like size, cost, consumables and more. Those became our marching orders for the rest of the development process. As the process moved forward we began creating mockups made of foamboard cut with razor blades. Then, once we moved on to 3D CAD models we started producing 3D printed parts on an in-house stereolithography (SLA) system.”
Griffin explains that there was no sharp transition from sketches to CAD models or from foamboard to SLA. The various processes overlapped, and over the course of the project, designs were periodically shared with focus groups of veterinary technicians. “We wanted feedback from the folks who’d be running the instrument in a lab,” he says. “We didn’t have an unlimited budget, so we proceeded step-by-step to make sure the new model would do exactly what we and our users wanted and do it at an affordable price.”
The development team planned to produce five generations of prototypes:
- Generation 1 - Focus using the robot’s movement to reduce the number of motors from 14 to six.
- Generation 2 - Address the need to put fluid onto slides for analysis
- Generation 3 - Add optics to examine the fluid
- Generation 4 - Replace generic controllers and software with proprietary boards and software
- Generation 5 – Replace all layered plastic parts with solid parts, either machined or injection molded, add the instrument’s exterior skin, and the incorporate final, more advanced software
A final verification version would then tested and moved on to production.
“This was my first experience with Proto Labs,” says Griffin. “One of our mechanical engineers had previous experience with the company, having successfully used Proto Labs’ Firstcut division for machined parts when our in-house machine shop was overloaded. We started using their machined parts as development of the Catalyst One progressed.
“In generations one through four, we were making up to 10 test machines at a time, so we needed that number of each part. In the early generations we weren’t as concerned with reliability so we made most of the parts in-house on our 3D printer. Starting with Generation 2, and increasingly in later generations, function became an issue, so we began having Firstcut machine some of the parts. That allowed us to use materials like Delrin that we’d be using in production. In the later generations Firstcut was making as many as 10 different parts for each of the machines we were testing.
“By Generation 5 we weren’t using any SLA parts anymore. Some parts were still being machined by Firstcut, but our Proto Labs’ customer service rep suggested that some parts would cost less to mold than to machine. That was my introduction to Proto Labs’ Protomold division. It was a timely suggestion since we were going to produce 30 machines in the verification phase and run them till they broke in real-world conditions. At that volume Firstcut’s machined parts would have been much more expensive, so we started using Protomold for some of our Generation 5 parts.
“In the verification phase all plastic parts will be molded. 70 percent will use steel tooling; the rest will be made by Protomold in aluminum molds. I’ve been astounded at what Proto Labs can do and how fast they can do it. I can’t imagine the software they use to turn our CAD models into toolpaths, and their ProtoQuote software, which analyzes 3D CAD designs and suggests changes, leaves me dumbfounded.
“It was easy to decide when to transition from Firstcut to Protomold, particularly when Firstcut’s quote for 30 machined parts was over 4X Protomold’s quote for 50 of the same parts. The whole process has gotten us thinking about new ways we could go to market. Working with Proto Labs lets us take chances at moderate cost. With hard tooling, quick turn means four to six weeks; Protomold can deliver molded parts in a few days, so even if I make a serious mistake I still come out ahead. That’s important because I left ‘perfect’ at home today.”